xj cancer

So are the xj's pretty succeptable to rust through in the rear floor pan, cargo pan area? We had my brothers 93 up on the hoist the other day and saw a small rust through in the right rear floor pan area, We decided to pull the carpet up and damn! rust and moisture everywhere!We ended up cutting out a 4-5 inch strip starting at the lower seat mounting bolt right to the rear hatch area (almost even with the unibody rails) on both sides to get rid of the rusted area and welding in some new steel along with a few other small spots.I was very suprised it could be that rusty and go unnoticed until now.I am more than sure my 89 xj has a little because the windows fog up pretty easy in the rear,I'm afraid to look until I have time to Fix it. I think the cut/patch/seal/rustproof will be fine for his daily driver. I do alot of wheeling and flex her pretty good am I better of to get complete replacement panels and weld them in or cut and repair?Damn Rust!!

A lot of it is the carpet padding, holds water for a long time and takes forever to dry out. Some type of synthetic padding would have been a real plus.
Areas with some sort of leak, may seldom if ever dry out. Tracking road salt onto the carpet just aggrivates things (it eventually finds it's way into the padding and contact with the metal).
I've had pretty good luck, painting the floor pan with interior (odorless) undercoating wax. I take the extra time and treat the floor pans anytime I have the carpet up. I also clean and treat the inside of the doors.
I use regular old aluminum foil to cover the wax, so the padding doesn't stick.
Rust throughs and serious cancer require surgery.